Conventionally, there has been a capacitor made by inserting a capacitor element into a metal case. The metal case is cylinder-shaped, closed at one end, and open at another end. After the capacitor element is inserted into the metal case, the opening at another end is blocked by a terminal block. The terminal block, which has an external terminal connected with an internal terminal of the capacitor element, is fixed on the opening edge of the metal case (see Patent Document 1, for example).
On the other hand, a conventional heat dissipation structure of a capacitor module in which plural capacitors are connected is a heat sink to which a plurality of assembled batteries is connected via a thermal conductive member, and cooling liquid flows through internal space of the heat sink (see Patent Document 2, for example).    Patent Document 1: Japanese Patent Application Laid-Open No. 2002-252151    Patent Document 2: Japanese Patent Application Laid-Open No. 2005-26219